Use HEAD instead of GET inside exists? Closes #11062 [bscofield]

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@8827 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

activeresource/CHANGELOG

 *SVN*
 
+* Use HEAD instead of GET in exists? [bscofield]
+
 * Fix small documentation typo.  Closes #10670 [l.guidi]
 
 * find_or_create_resource_for handles module nesting.  #10646 [xavier]

activeresource/lib/active_resource/base.rb

@@ -436,7 +436,13 @@ def delete(id, options = {})
       #   Note.exists(1349)
       #   # => false
       def exists?(id, options = {})
-        id && !find_single(id, options).nil?
+        if id
+          prefix_options, query_options = split_options(options[:params])
+          path = element_path(id, prefix_options, query_options)
+          response = connection.head(path, headers)
+          response.code == 200
+        end
+        # id && !find_single(id, options).nil?
       rescue ActiveResource::ResourceNotFound
         false
       end

activeresource/lib/active_resource/connection.rb

@@ -101,6 +101,12 @@ def post(path, body = '', headers = {})
       request(:post, path, body.to_s, build_request_headers(headers))
     end
 
+    # Execute a HEAD request.
+    # Used to ...
+    def head(path, headers= {})
+      request(:head, path, build_request_headers(headers))
+    end
+
 
     private
       # Makes request to remote service.

activeresource/lib/active_resource/http_mock.rb

@@ -9,7 +9,7 @@ def initialize(responses)
         @responses = responses
       end
 
-      for method in [ :post, :put, :get, :delete ]
+      for method in [ :post, :put, :get, :delete, :head ]
         module_eval <<-EOE, __FILE__, __LINE__
           def #{method}(path, request_headers = {}, body = nil, status = 200, response_headers = {})
             @responses[Request.new(:#{method}, path, nil, request_headers)] = Response.new(body || "", status, response_headers)
@@ -56,7 +56,7 @@ def #{method}(path, body, headers)
       EOE
     end
 
-    for method in [ :get, :delete ]
+    for method in [ :get, :delete, :head ]
       module_eval <<-EOE, __FILE__, __LINE__
         def #{method}(path, headers)
           request = ActiveResource::Request.new(:#{method}, path, nil, headers)

activeresource/test/base_test.rb

@@ -36,6 +36,11 @@ def setup
       mock.put    "/people//addresses/1.xml",  {}, nil, 404
       mock.delete "/people//addresses/1.xml",  {}, nil, 404
       mock.post   "/people//addresses.xml",    {}, nil, 404
+      mock.head   "/people/1.xml",             {}, nil, 200
+      mock.head   "/people/99.xml",            {}, nil, 404
+      mock.head   "/people/1/addresses/1.xml", {}, nil, 200
+      mock.head   "/people/1/addresses/2.xml", {}, nil, 404
+      mock.head   "/people/2/addresses/1.xml", {}, nil, 404
     end
   end
 

activeresource/test/connection_test.rb

@@ -27,6 +27,7 @@ def setup
       mock.delete "/people/2.xml", @header, nil, 200
       mock.post   "/people.xml",   {}, nil, 201, 'Location' => '/people/5.xml'
       mock.post   "/members.xml",  {}, @header, 201, 'Location' => '/people/6.xml'
+      mock.head   "/people/1.xml", {}, nil, 200
     end
   end
 
@@ -105,6 +106,12 @@ def test_get
     assert_equal "Matz", matz["name"]
   end
 
+  def test_head
+    response = @conn.head("/people/1.xml")
+    assert response.body.blank?
+    assert_equal 200, response.code
+  end
+
   def test_get_with_header
     david = @conn.get("/people/2.xml", @header)
     assert_equal "David", david["name"]